Quinolinic acid (2,3-pyridine-dicarboxylic acid) has a wide variety of applications as a precursor of chemicals, such as medical and agricultural chemicals, dyes, or the like.
Quinolinic acid can be prepared by chemical or biological synthesis methods. In a chemical manner, quinolinic acid is generally prepared by oxidation of quinoline. In a biological manner, a method of producing quinolinic acid in an Escherichia coli (E. coli) strain is disclosed, wherein the E. coli strain enhances the expression of two enzymes, L-aspartate oxidase (NadB) and quinolinate synthase (NadA), in an E. coli of which quinolinate phosphoribosyltransferase (NadC) activity is eliminated.
KefA is a membrane protein belonging to a mechanosensitive (MS) channel present in a microorganism, such as E. coli, and has a known function of introducing an ion and a solute into a cell through a cell membrane in a non-specific manner. KefA in E. coli constitutes a potassium (K+) efflux system along with KefB and KefC, and more particularly, KefA is known to have an important role in the efflux of K+ upon osmotic down shock (J. Bacteriol. 169, 3743-3749, 1987). In addition, it has been reported that, when a gene of KefA undergoes mutation in E. coli, cells become more sensitive to concentrations and pressures of K+, compared to wild-type cells (J. membrane Biol. 150, 143-152). However, as described above, most studies mainly focus on KefA associated with the control of potassium ions in cells, whereas any study on KefA associated with the production of quinolinic acid has not yet been found.
In this regard, the present inventors carried out research about correlation between the modified activity of MS channel proteins and the production of quinolinic acid in high concentrations, thereby completing a method of producing quinolinic acid in high yields.